Solve the following problems: 1. A rock weighs 1.6 N on the moon. If the gravitational field strength on the moon is 1.6 N/kg, what is the mass of the rock? 2. Mwanahawa buys 400 books for 5600. She s

The weight of the rock ($W$) is $1.6 \text{ N}$.
The gravitational field strength ($g$) on the moon is $1.6 \text{ N/kg}$.
The formula relating weight, mass, and gravitational field strength is:

$$W = m \times g$$

where $m$ is the mass.

To find the mass ($m$), we rearrange the formula:

$$m = \frac{W}{g}$$

Substitute the given values:

$$m = \frac{1.6 \text{ N}}{1.6 \text{ N/kg}}$$ $$m = 1 \text{ kg}$$

The mass of the rock is $\boxed{\text{1 kg}}$.

:

Mwanahawa buys 400 books for $5600.

$$\text{Total CP} = 5600$$

She sells 200 books at $240 each.

$$\text{Revenue from 1st batch} = 200 \times 240 = 48000$$

She sells 140 books at $160 each.

$$\text{Revenue from 2nd batch} = 140 \times 160 = 22400$$

Remaining books = Total books - Books sold in 1st batch - Books sold in 2nd batch

$$\text{Remaining books} = 400 - 200 - 140 = 60$$

She sells the remaining 60 books at $55 each.

$$\text{Revenue from remaining books} = 60 \times 55 = 3300$$

$$\text{Total SP} = \text{Revenue from 1st batch} + \text{Revenue from 2nd batch} + \text{Revenue from remaining books}$$ $$\text{Total SP} = 48000 + 22400 + 3300 = 73700$$

$$\text{Profit} = \text{Total SP} - \text{Total CP}$$ $$\text{Profit} = 73700 - 5600 = 68100$$

$$\text{Percentage Profit} = \frac{\text{Profit}}{\text{Total CP}} \times 100\%$$ $$\text{Percentage Profit} = \frac{68100}{5600} \times 100\%$$ $$\text{Percentage Profit} = 12.160714... \times 100\%$$ $$\text{Percentage Profit} \approx 1216.07\%$$

Mwanahawa's percentage profit is approximately \boxed{\text{1216.07%}}.